3 bank battery charger

[sea-esta]

I just bought a boat that has a 3 bank pro onboard battery charger that was set up to run a 36 volt electric motor. I would like to remove the electric motor yet still utilize these batteries and charger. There is a seperate starting battery.(4 batteries total) The boat has a 200hp out board with a 60 amp atlt. I would like to know what the best way would be to still utilze the charger and additional batteries. The boat has a lot of accesories that I would like to keep off the starting battery. Is there a way to charge all of the batteries from both the charger and the alternator? Is an isolater and some type of switch needed? Thanks in advance for any info, diagrams, or sugestions.

 

[drewpster]

Re: 3 bank battery charger

A couple of questions. What make and model charger do you have. What type batterys are they? And what was this motor used for?

 

[sea-esta]

Re: 3 bank battery charger

The charger is a Dual Pro Charging systems International. The model is the Three Bank Pro Se with 10 amps per bank. The three batteries that were used to run a Minn-kota 36 volt trolling motor are size 27 Trogan deep cycle with 100 amp hours. The fourth battery is a 875 CA strarting baterry.

Thanks for any help!

 

[Silvertip]

Re: 3 bank battery charger

1) Do you have any accessories that require anything other than 12V dc? 2) Is your 12V current draw really high enough that you actually need four batteries? 3) The charger can be used but we need to know what you really want to accomplish and why you feel you need all that power.

 

[sea-esta]

Re: 3 bank battery charger

All accessories are 12 volt. Two livewells with aerators, wash down pump, interior cabin and cockpit lighting, electronics, stereo ect.. everything now is hooked up to the starting battery, with the deep cycles used in series to run the 36 volt trolling motor.( which I no longer use) I'm sure 4 batteries is over kill, I would just like to make use of the charger for sure and the batteries (some or all ?) that are allready there. I would also like to have a back up starting source.

Thanks.

 

[Silvertip]

Re: 3 bank battery charger

How good are you at understanding battery switches, isolators, and VSR's and what they accomplish? There are several ways to use all four batteries and you will get many opinions as to which is the best way to do it. Only you can decide what's best for you. Are you capable of doing the wiring and equipment install yourself? I'm going to draw you a schematic for a manually switched system. It will be the least expensive to install, and will provide the most flexibility. Stay tuned.

 

[sea-esta]

Re: 3 bank battery charger

I would like to do the wiring myself. I'm not an electrician but a good schematic I think I could follow.

Thanks for any help!

 

[Silvertip]

Re: 3 bank battery charger

Here ya go. As I warned you, you have opened a door to many options. Pick the one that works best for you.

This system uses two inexpensive OFF-1-BOTH-2 battery switches. You will use two of the batteries for powering accessories. The other two will be for engine starting duty. With both switches in the OFF position, the entire electrical system is dead. No chance of leaving anything on to run the batteries down. Lets discuss the START switch first. You can set this switch to 1, BOTH or 2 for starting. Only the battery you have selected will charge. When set to BOTH, both will charge. Typical use would be to start on 1 or 2 and switch to BOTH when under way. NEVER set BOTH of these battery switches to OFF with the engine running. This will kill the regulator. That also applies to a dual battery-single switch application.

Now for the ACCESSORY switch. Same principle applies. Run accessories off BAT 1. Switch to BAT 2 if BAT 1 runs down. When the engine is running, you can set this switch to OFF if you like to ensure the two starting batteries have all of the available charging current. If those batteries are ok you can switch to 1, 2 or BOTH on the accessory switch to charge them at the same time.

I didn't show it on the diagram, but all of your accessories will be wired to the COMMON terminal on the accessory switch. Engine related accessories go to the COMMON terminal on the STARTING switch.

Let's say you ran the two starting batteries down. You can set the START switch to OFF, set the ACCESSORY switch to 1, 2, or BOTH and start the engine off those batteries as well.

Your charger outputs (3 sets of leads) can be connected directly to any three batteries you wish. I would suggest that two of them go to the starting batteries and the third to either of the auxiliary batteries.

 

[sea-esta]

Re: 3 bank battery charger

Thank you for the info and the nice schematic Silvertip.
In what position would the switches need to be in when the charger is pluged in? Would it be a good idea to have a fuse/breaker inline some where? Also any need for an isolator.


Thanks again for your help!!

 

[Silvertip]

Re: 3 bank battery charger

The chargers are connected directly to the batteries so depending on how you set the switches, you can charge all four. Setting both switches to OFF would charge the three batteries that you have the charger outputs connected to. Leaving the ACC switch OFF and the START switch to BOTH would charge all four although the charger output connected to the start battery would have to charge both start batteries. That's not a problem since one output can easily handle that at start batteries rarely get deeply discharged. Just think about the system when making selections. If both switches are set to BOTH you have all four batteries in parallel which makes for one giant amount of power. At anchor I would have the START switch OFF and the ACC switch on 1, BOTH, or 2, and I would probably use the BOTH setting. When you get ready to leave, set the START switch to BOTH, fire the engine and go. All four batteries will charge. With as much power as you have I can't imagine ever using ACC settings other than OFF or BOTH. You do realize that all these connections need to be the same cable size as the engine battery cables!

 

[sea-esta]

Re: 3 bank battery charger

I don't wish to complicate this but is there a reason you might want to use an isolater in this setup? also any need for any inline fuses?
Thanks for your time and knowledge.

 

[Silvertip]

Re: 3 bank battery charger

You don't have a fuse or breaker in the battery cables now and you don't need them in this system either. Remember that the starter is the biggest draw on this system so all connections must be the same size or larger than the battery cables.

For what you want to do, isolator(s) will not work. They allow current to pass in one direction but not the other. Therefore they are used to isolate two batteries and prevent one from drawing down the other but allow charging both. You could certainly use them, but to retain the flexibility of this system you would still need the battery switches. In addition, there is a voltage drop across an isolator and with this many batteries you need every bit of current to reach them.

 

[sea-esta]

Re: 3 bank battery charger

Currently there is a push button circuit breaker between the engine positive lead and the starting battery. Does this provide any protection? If i opted to just use three of the batteries would that change things? which one would you eliminate?

 

[Silvertip]

Re: 3 bank battery charger

That circuit breaker is not in the large positive battery cable is it? It's probably in the charging line from the voltage rectifier/regulator. Sure it changes things. You have one less battery and less wiring, but you still have two switches to accomplish your originally stated task. This entire system can be simplified where both switches and one battery are eliminated and all connections between them removed so that the only connections you have are to the starting battery. Your battery charger then connects directly to each of the three batteries. Head to an auto store and buy a set of jumper cables. Now if your start battery is dead, you can jump from any battery. But isn't that what the switches did? You cannot draw current backwards through an isolator -- that's why it's called an isolator. It is used only for charging puposes. If you have nothing else to run off the other batteries they are just going along for the ride. You could also hook all four, three, or two batteries in parallel with no switches, and no isolators. The net result is you have one gigantic battery that you could not possibly run down without vaporizing the starter. Give me concrete wants and don't wants and I can probably help, but I can't read your mind. If I really had a need for four batteries and wanted maximum flexibility, the diagram I gave you is the system I would build for myself.